(1) An oxazole compound substituted by a trihalomethyl group which is represented by the following formula (PAG1), and an s-triazine compound substituted by trihalomethyl groups which is represented by the following formula (PAG2); ##STR7## wherein R1 is a substituted or unsubstituted aryl or alkenyl group, R2 is a substituted or unsubstituted aryl, alkenyl or alkyl group or --CY3, and Y is a chlo